A square numeric matrix representing interaction coefficients between
species. a_ij is the per-capita interaction strength of species j
on species i. It expresses the change in carrying capacity of species i
by a single individual of species j.
This data is compatible with n1_map_eg.tif and K_map_eg.tif maps.
a_egA numeric matrix with 4 rows and 4 columns containing interaction coefficients.